Image pickup apparatus

ABSTRACT

An image pickup apparatus which is capable of effectively removing dust attached to an optical member due to mounting/removing of a photographic lens in a power-off state, to thereby prevent degradation of image quality. In the image pickup apparatus, when position information of a contact brush that moves in a manner interlocked with mounting/removing of the photographic lens differs immediately after execution of power-on operation from position information obtained immediately after execution of power-off operation, it is determined that photographic lens mounting/removing operation was carried out during power-off, and a camera microcomputer outputs a warning advising cleaning of the optical member.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image pickup apparatus, such as adigital single-lens reflex camera, on which has a photographic lens isremovably held.

2. Description of the Related Art

Conventionally, in an image pickup apparatus of the above-mentionedtype, countermeasures are taken to prevent degradation of image qualitydue to dust attached to an optical member, such as a low-pass filter,disposed between a photographic lens and an image pickup element thatconverts light incident thereon from the photographic lens into anelectric signal.

For example, an image pickup apparatus has been made commerciallypractical in which a member disposed between a photographic lens and animage pickup element is ultrasonically vibrated to thereby remove dustattached to the member. Further, there have been proposed an imagepickup apparatus in which the number of times of attachment/detachmentof a detachable low-pass filter is counted, and when the count reaches apredetermined value, cleaning of the low-pass filter is recommended (seee.g. Japanese Laid-Open Patent Publication (Kokai) No. 2000-125152), andanother in which a dust-removing mechanism is operated in response tothe mounting of a photographic lens (see e.g. Japanese Laid-Open PatentPublication (Kokai) No. 2003-330082).

However, neither Japanese Laid-Open Patent Publication (Kokai) No.2000-125152 nor Japanese Laid-Open Patent Publication (Kokai) No.2003-330082 discloses a technique for coping with dust attached to aphotographic lens mounted in a power-off state of the image pickupapparatus or with a battery removed from the apparatus. When consideringsituations in which image pickup apparatuses capable of exchangingphotographic lenses are used, exchange of photographic lenses isperformed more often in the power-off state than in the power-on state.However, in the image pickup apparatuses disclosed in theabove-mentioned patent Publications, in each of which mounting/removingof a photographic lens is electrically detected, it is impossible todetect the exchange of photographic lenses performed in the power-offstate.

On the other hand, if the dust-removing mechanism is configured to beoperated whenever the power is turned on, irrespective of whether or nota lens mounting/removing operation has been performed, an inconvenienceoccurs when the power is repeatedly turned on and off over a short timeperiod without mounting or demounting a lens or when the apparatusreturns from a sleep state (power-saving state where the operation ofthe apparatus is temporarily stopped) to an ON state. That is, thedust-removing mechanism is operated even when it is not required, whichis undesirable in terms of power consumption and operation durability.Therefore, it is important to be able to detect, when the power isturned on again, whether or not a photographic lens-mounting/removingoperation has been performed in the power-off state.

SUMMARY OF THE INVENTION

The present invention provides an image pickup apparatus which iscapable of detecting, when the power is turned on again, whether or nota photographic lens-mounting/removing operation has been performed inthe power-off state so as to effectively remove dust attached to anoptical member, to thereby prevent degradation of image quality.

According to the present invention, there is provided an image pickupapparatus on which a photographic lens is removably held, comprising amovable unit configured to move in a manner interlocked withmounting/removing of the photographic lens, a position detecting unitconfigured to detect a position of the movable unit, and a determinationunit configured to determine, based on position information on themovable unit detected by the position detecting unit, whether or not thephotographic lens was mounted/removed.

With the arrangement of the present invention, if information on theposition of the movable unit that moves in a manner interlocked with themounting/removing of the photographic lens differs upon turn-on of thepower from the information obtained immediately before turn-off of thepower, it is determined that a photographic lens mounting/removingoperation was performed in the power-off state.

A dust-removing mechanism can be driven based on the result of thedetermination, so that it is possible to effectively remove dustattached to the optical member, to thereby avoid picking up the image ofthe dust and prevent degradation of image quality.

The image pickup apparatus an comprises a processing unit configured tocarry out processing for cleaning an optical member when thedetermination unit determines that the photographic lens wasmounted/removed.

The optical member can be disposed between an image pickup element forconverting light incident thereon from the photographic lens into anelectric signal, and the photographic lens.

The image pickup apparatus can comprise a storage unit configured tostore the position information on the movable unit detected by theposition detecting unit, and the determination unit can determine, basedon the position information stored in the storage unit, whether or notthe photographic lens was mounted/removed.

When the position information on the movable unit detected afterexecution of a power-off operation and the position information on themovable unit detected after execution of a power-on operation differfrom each other, the determination unit can determine that thephotographic lens was mounted/removed.

The image pickup apparatus can comprise an unlocking member configuredto release engagement of the photographic lens, and the movable unit canmove in a manner interlocked with an operation of the unlocking member.

The image pickup apparatus can comprise a movement-converting unitincluding a rectilinear slide member configured to be capable of movingalong an optical axis of the photographic lens in a manner interlockedwith the operation of the unlocking member, and a rotary member providedwith the movable unit and connected to the rectilinear slide member viaa cam engagement part, the movement-converting unit converting movementof the rectilinear slide member along the optical axis to rotation ofthe rotary member by cam action of the cam engagement part.

The image pickup apparatus can comprise an engagement unit forengagement with the photographic lens, and the movable unit can move ina manner interlocked with an operation for mounting/removing thephotographic lens to/from the engagement unit.

The image pickup apparatus can comprise a movement-converting unitincluding a rectilinear slide member configured to be capable of movingalong an optical axis of the photographic lens in a manner interlockedwith an operation for mounting/removing the photographic lens to/fromthe engagement unit, and a rotary member provided with the movable unitand connected to the rectilinear slide member via a cam engagement part,the movement-converting unit converting movement of the rectilinearslide member along the optical axis to rotation of the rotary member bycam action of the cam engagement part.

The engagement unit have a plurality of arcuate bayonet lugscircumferentially arranged, and the rectilinear slide member is disposedbetween circumferentially adjacent ones of the bayonet lugs.

The position detecting unit can include a conductive member provided inthe movable unit, and an electric circuit member having a plurality ofconductive traces, and the electric circuit member can detect at leasttwo items of position information each according to a position of theconductive member.

The image pickup apparatus can comprise an unlocking member configuredto release engagement of the photographic lens, and a drive unitconfigured to drive the movable unit, and the movable unit can beconfigured to be movable between a first position and a second position,and when a power-off operation is carried out, the movable unit can bedriven by the drive unit to shift to the first position to be held inthe first position, and when the unlocking member is operated, themovable unit can shift to the second position in a manner interlockedwith the operation of the unlocking member, to be held in the secondposition, wherein when the position information on the movable unitdetected after execution of the power-off operation and the positioninformation on the movable unit detected after execution of the power-onoperation differ from each other, the determination unit can determinethat the photographic lens was mounted/removed.

The image pickup apparatus can comprise an unlocking member configuredto release engagement of the photographic lens, and a drive unitconfigured to drive the movable unit, and the movable unit can beconfigured to be movable between a first position and a second position,and the movable unit can be driven by the drive unit to shift to thefirst position to be held in the first position, when a power-offoperation is carried out, and shifts to the second position in a mannerinterlocked with the operation of the unlocking member, to be held inthe second position, wherein when the position information on themovable unit detected after execution of the power-off operation and theposition information on the movable unit detected after execution of apower-on operation differ from each other, the determination unit candetermine that the photographic lens was mounted/removed.

The engagement unit can have a plurality of arcuate bayonet lugscircumferentially arranged, and the movable unit can be disposed betweencircumferentially adjacent ones of the bayonet lugs.

The movable unit can be configured to be movable along the optical axisof the photographic lens, and can be provided with a toggle spring forurging the movable unit toward one side or an opposite side in adirection along the optical axis.

The position detecting unit can optically detect the position of themovable unit.

The position detecting unit can electrically detect the position of themovable unit.

The image pickup apparatus comprises a vibrator unit configured toprovide vibration to the optical member, and when the determination unitdetermines that the photographic lens was not mounted/removed, theprocessing unit can drive the vibrator unit by a first control, and whenthe determination unit determines that the photographic lens wasmounted/removed, the processing unit can drive the vibrator unit by asecond control.

The first control causes the vibrator unit not to be driven, and thesecond control causes the vibrator unit to be driven for a predeterminedtime period.

The first control can cause the vibrator unit to be driven for apredetermined time period, and the second control can cause the vibratorunit to be driven for a longer time period than the predetermined timeperiod.

When the determination unit determines that the photographic lens wasmounted/removed, the processing unit can carry out warning processing toadvise cleaning of the optical member.

The above and other objects, features, and advantages of the inventionwill become more apparent from the following detailed description takenin conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a digital single-lens reflex cameraaccording to a first embodiment of the present invention, as viewed froman object side.

FIG. 2 is a control block diagram of the digital single-lens reflexcamera according to the first embodiment.

FIG. 3 is an exploded perspective view of an unlock button and amechanism operated in a manner interlocked with operation of the unlockbutton.

FIG. 4 is a cross-sectional view useful in explaining a state where theunlock button stays unoperated.

FIG. 5 is a perspective view of a cover cam and a button cam, as viewedfrom inside the camera.

FIG. 6 is a perspective view of a rotary cam member, as viewed from theobject side.

FIG. 7 is a view of the unlock button in the unoperated state.

FIG. 8 is a view of the unlock button in a state being operated.

FIG. 9 is a view of the unlock button in a state where an operationthereof has been completed.

FIG. 10 is a plan view of conductive traces arranged on a phase flexibleprinted circuit board, as viewed from a photographer side.

FIG. 11 is a plan view of the conductive traces with a contact brushpositioned on a conductive trace A.

FIG. 12 is a plan view of the conductive traces with the contact brushpositioned on a conductive trace B.

FIG. 13 is a flowchart useful in explaining an example of operation ofthe digital single-lens reflex camera according to the first embodiment.

FIG. 14 is a perspective view of a lens mount and its surrounding of adigital single-lens reflex camera according to a second embodiment ofthe present invention, as viewed from the object side.

FIG. 15 is a perspective view of a mirror box, as viewed from thephotographer side.

FIG. 16 is a cross-sectional view of the mirror box with the lens mountrigidly secured thereto.

FIG. 17 is a perspective view of the lens mount.

FIG. 18 is a perspective view of the lens mount in a state where aphotographic lens mount of a photographic lens unit has been fittedtherein.

FIG. 19 is a perspective view of the lens mount in a state where thephotographic lens mount has been rotated to a predetermined phase fromthe state shown in FIG. 18.

FIG. 20 is a view of a portion of the lens mount in a state where thephotographic lens unit is being mounted therein.

FIG. 21 is a view of a portion of the lens mount in a state where thephotographic lens unit has been pushed therein at a predetermined phasewhen the photographic lens unit is mounted.

FIG. 22 is a view of a portion of the lens mount in a state where thephotographic lens unit is being rotated to the predetermined phase.

FIG. 23 is a view of a portion of lens in a state where the photographiclens unit has been fully rotated to the predetermined phase andcompletely mounted.

FIG. 24 is a perspective view of an unlock button and its surrounding ofa digital single-lens reflex camera according to a third embodiment ofthe present invention.

FIG. 25 is an exploded perspective view of a mechanism operated in amanner interlocked with the operation of the unlock button.

FIG. 26 is a see-through view useful in explaining the internalconstruction of the mechanism operated in a manner interlocked with theoperation of the unlock button.

FIG. 27 is a view of the unlock button in an operated state.

FIG. 28 is a view of the unlock button in a state released afterdepression.

FIG. 29 is a control block diagram of the digital single-lens reflexcamera according to the third embodiment.

FIG. 30 is a flowchart useful in explaining an example of operation ofthe digital single-lens reflex camera according to the third embodiment.

FIG. 31 is a perspective view of an unlock button and its surrounding ofa digital single-lens reflex camera according to a fourth embodiment ofthe present invention.

FIG. 32 is an exploded perspective view useful in explaining a mechanismoperated in a manner interlocked with a bayonet engagement operation.

FIG. 33 is a cross-sectional view of a mirror box with a lens mountrigidly secured thereto.

FIG. 34 is a cross-sectional view of essential parts of a digitalsingle-lens reflex camera according to a fifth embodiment of the presentinvention.

FIG. 35 is a control block diagram of the digital single-lens reflexcamera according to the fifth embodiment.

FIG. 36 is a flowchart useful in explaining an example of operation ofthe digital single-lens reflex camera according to the fifth embodiment.

FIG. 37 is a flowchart useful in explaining an example of operation of adigital single-lens reflex camera according to a sixth embodiment of thepresent invention.

FIG. 38 is a control block diagram of the digital single-lens reflexcamera according to the sixth embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described in detail with reference tothe drawings showing preferred embodiments thereof.

FIG. 1 is a perspective view of a digital single-lens reflex cameraaccording to a first embodiment of the present invention, as viewed froman object side, in a state where a photographic lens unit is removedtherefrom. FIG. 2 is a control block diagram of the digital single-lensreflex camera.

As shown in FIG. 1, the digital single-lens reflex camera (image pickupapparatus) according to the first embodiment has a lens mount 105provided as a part for use in mounting the photographic lens unit A16(see FIG. 2) to a camera body 100 via a bayonet mechanism. The camerabody 100 has communication pins 114 projecting therefrom for identifyingthe type of the photographic lens unit A16 mounted to the camera body100.

Next, an operation carried out by a photographer before shooting will bedescribed with reference to FIGS. 1 and 2.

As shown in FIGS. 1 and 2, when the photographer mounts the photographiclens unit A16 to the camera body 100 and turns a power switch member 102to its ON position, a camera microcomputer A01 activates the camera andrecognizes the photographic lens unit A16. When the photographer sets amode dial 101 to a desired shooting mode and then operates an electronicdial 103, the camera microcomputer A01 sets shooting conditions based onsignals from operation members A02 (members including the power switchmember 102, and buttons and dials, referred to hereinafter, used by thephotographer for operating the camera, and collectively illustrated inFIG. 2).

If the photographer depresses a release button 104 after setting theshooting conditions, the camera microcomputer A01 drives sensors A03.For example, ranging is performed by an AF unit 116, and light meteringis performed by a light-metering unit, not shown. Further, a built-instroboscope 110 is driven to a predetermined position, if necessary.Then, when the release button 104 is further depressed, the cameramicrocomputer A01 drives a shooting drive unit A04. This causes a quickreturn mirror 115 to be driven to retreat from a photographic opticalpath, and at the same time a shutter curtain of a shutter A05 is alsodriven to retreat from the photographic optical path, wherebyimage-forming light from an object passes through an optical member A13to cause exposure of an electronic image pickup element A06. An electricsignal subjected to photoelectric conversion by the electronic imagepickup element A06 is converted to predetermined data by an imageprocessing unit A07, and then recorded in an external memory A08.

In the case of removing the photographic lens unit A16 from the camerabody 100, the photographer depresses a photographic lens unlock button(unlocking member) 107 (hereinafter simply referred to as “the unlockbutton 107”) held in a front cover 112. When the unlock button 107 isdepressed, a photographic lens lock pin 113 (hereinafter simply referredto as “the lock pin 113”) is operated in an interlocked fashion to beretracted from the lens mount 105 into the camera body 100. When thelock pin 113 is retracted into the camera body 100, the photographiclens unit A16 is made rotatable, so that the photographer can rotate theentire photographic lens unit A16 to release bayonet engagement, wherebythe photographic lens unit A16 can be removed from the camera body 100.

FIG. 3 is a view of the unlock button 107 and a mechanism operated in amanner interlocked with the operation of the unlock button 107. In FIG.3, the front cover 112 is shown broken away.

As shown in FIG. 3, the unlock button 107 has a fitting shaft 107-aextending therefrom for fitting in the front cover 112. A compressionspring 107-1 is fitted on the engaging shaft 107-a, for causing theunlock button 107 to be protruded from the front cover 112 toward anobject side. The front cover 112 is formed therethrough with a fittinghole 112-b for holding the unlock button 107 in a manner movable alongthe optical axis of a photographic lens. Further, the front cover 112has a cam part 112-a (hereinafter referred to as “the cover cam 112”)formed on a side thereof facing the inside of the camera.

A rectilinear slide cam member (slide member) 107-2 is rigidly securedto the end of the fitting shaft 107-a of the unlock button 107 withscrews, not shown, from inside the camera. This prevents the unlockbutton 107 from falling off the front cover 112 due to the urging forceof the compression spring 107-1.

The rectilinear slide cam member 107-2 is formed with a cam part 107-2-a(hereinafter referred to as “the button cam 107-2-a”). The unlock button107 and the rectilinear slide cam member 107-2 are integrally secured toeach other, and are held in the front cover 112 in a manner movablealong the lens optical axis with their rotation restricted.

A phase flexible printed circuit board (position sensor unit) 107-3having phase traces provided thereon is fixed to an inner wall of thefront cover 112 facing the inside of the camera, and a contact brush(movable unit) 107-4 is in contact with the phase flexible printedcircuit board 107-3, for phase trace detection. The contact brush 107-4is fixed to a rotary cam member (rotary member) 107-5 that rotates in amanner interlocked with the operation of the unlock button 107.

The rotary cam member 107-5 is formed with a cam part 107-5-a(hereinafter referred to as “the rotary cam 107-5-a”). The rotary cam107-5-a engages with the cover cam 112-a and the button cam 107-2-a torotate the rotary cam member 107-5. The rotary cam member 107-5 has afitting shaft 107-5-b extending therefrom. The fitting shaft 107-5-b isfitted in a base plate-fitting hole 107-7-a formed in a cam base plate107-7 in a manner movable along and rotatable about the lens opticalaxis.

Fitted on the fitting shaft 107-5-b extending from the rotary cam member107-5 is a compression spring 107-6 for urging the rotary cam member107-5 toward the object side. The cam base plate 107-7 is rigidlysecured to the front cover 112 with screws, not shown.

FIG. 4 shows the unlock button 107 in an unoperated state. In FIG. 4,the front cover 112 is shown broken away.

As shown in FIG. 4, the lock pin 113 and a linkage member 113-1interlocked therewith are disposed such that they can be brought intocontact with the unlock button 107. The lock pin 113 is urged by a lockpin spring 113-2 to protrude from the lens mount 105. The unlock button107 is urged toward the object side by the compression spring 107-1disposed between the front cover 112 and the unlock button 107 itself,and is held in a predetermined position by the rectilinear slide cammember 107-2 as a stopper. Unless the unlock button 107 is depressed,the cover cam 112-a and the rotary cam 107-5-a are held in contact witheach other by the urging force of the compression spring 107-6 toprevent unintentional rotation of the rotary cam member 107-5.

FIG. 5 is a perspective view of the cover cam 112-a and the button cam107-2-a, as viewed from inside the camera.

As shown in FIG. 5, the button cam 107-2-a is disposed inward of thecover cam 112-a. The cover cam 112-a is integrally formed with the frontcover 112 on the side of the front cover 112 facing the inside of thecamera. The button cam 107-2-a is allowed to move along the lens opticalaxis in accordance with movement of the unlock button 107, but rotationof the button cam 107-2-a is restricted. Each of the cover cam 112-a andthe button cam 107-2-a is comprised of six cam parts each arranged atvery 600 position, and the cover cam 112-a and the button cam 107-2-aare disposed in a manner shifted in phase from each other byapproximately 30°.

FIG. 6 is a perspective view of the rotary cam member 107-5, as viewedfrom the object side.

As shown in FIG. 6, the rotary cam 107-5-a is comprised of three camparts each arranged at every 120° position. The length of each of thecam parts is set such that the rotary cam 107-5-a can be brought intocontact with the cover cam 112-a and the button cam 107-2-a. The rotarycam member 107-5 performs counterclockwise rotation, as viewed from theobject side, by having the rotary cam 107-5-a brought into contact withthe cover cam 112-a and the button cam 107-2-a.

FIG. 7 is a view of the unlock button 107 in the unoperated state. InFIG. 7, the front cover 112 is shown broken away.

As shown in FIG. 7, in a state where the unlock button 107 is notoperated, the cover cam 112-a and the rotary cam 107-5-a are held incontact with each other, and the contact brush 107-4 is in contact withthe phase flexible printed circuit board 107-3.

Then, when the unlock button 107 is depressed, as shown in FIG. 8, therectilinear slide cam member 107-2 moves toward a photographer sidetogether with the unlock button 107, whereby the button cam 107-2-astarts to be brought into contact with the rotary cam 107-5-a. When thebutton cam 107-2-a is brought into contact with the rotary cam 107-5-a,due to engagement of cam surfaces of the respective cams, the rotary cammember 107-5 starts rotation while moving toward the photographer side.When the rotary cam 107-5-a of the rotary cam member 107-5 is moved tobe closer to the photographer than the cover cam 112-a is, i.e. when therotary cam 107-5-a has moved to a position where it is not in contactwith the cover cam 112-a, the rotary cam member 107-5 has rotatedthrough approximately 30°.

When the unlock button 107 is in a depressed state, the rotary cammember 107-5 has been shifted to its photographer-side position, andtherefore the contact brush 107-4 is not in contact with the phaseflexible printed circuit board 107-3. Then, when the unlock button 107is released, the unlock button 107 and the rectilinear slide cam member107-2 start moving toward the object side by the urging force of thecompression spring 107-1.

AS the rectilinear slide cam member 107-2 moves toward the object side,the rotary cam member 107-5 is also moved toward the object side by theurging force of the compression spring 107-6. At this time, the rotarycam member 107-5 having been rotated through approximately 30° from aposition where it was before depression of the unlock button 107 startsto come into contact with a cam surface of the cover cam 112-a in aphase adjacent in the counterclockwise direction to a phase in which thecover cam 112-a was before depression of the unlock button 107. Then,the rotary cam member 107-5 is not only moved toward the object side bythe urging force of the compression spring 107-6, but also furtherrotated through approximately 30° by the cover cam 112-a.

FIG. 9 shows the unlock button 107 in a state where its operation hasbeen completed. In FIG. 9, the rotary cam member 107-5 has been rotatedthrough 600 from the state shown in FIG. 7 by a one-time operation ofthe unlock button 107, and held in the state. Since the rotary cammember 107-5 has been shifted to a predetermined object-side positionwhere it is engaged with the cover cam 112-a, the contact brush 107-4fixed to the rotary cam member 107-5 is in contact with the phaseflexible printed circuit board 107-3.

FIG. 10 is a plan view of conductive traces arranged on the phaseflexible printed circuit board 107-3, as viewed from the photographerside. As shown in FIG. 10, six different traces are each arranged on thephase flexible printed circuit board 107-3 at every 60° position so asto detect each of six positions of the rotary cam member 107-5 throughdetection of a conducting state. For example, FIG. 11 shows a positionof the contact brush 107-4 corresponding to FIG. 7. In FIG. 11, thecontact brush 107-4 is positioned on a trace A of the phase flexibleprinted circuit board 107-3. Further, FIG. 12 shows a position of thecontact brush 107-4 corresponding to FIG. 9. In FIG. 12, the contactbrush 107-4 is positioned on a trace B of the phase flexible printedcircuit board 107-3. Since the rotary cam member 107-5 is rotatedthrough 600 by a one-time operation of the unlock button 107, thecontact brush 107-4 fixed to the rotary cam member 107-5 is also rotatedthrough 60°, whereby the contact point part of the contact brush 107-4is shifted to an adjacent phase trace.

Although in the present embodiment, the cam parts of each of the covercam 112-a and the button cam 107-2-a are each arranged at every 60°position, and the phase flexible printed circuit board 107-3 is providedwith six conductive traces so as to identify six items of positioninformation, it suffices that at least two items of position informationcan be identified.

As described above, according to the present embodiment, once the unlockbutton 107 is operated so as to remove the photographic lens unit A16from the camera body 100, the contact brush 107-4 rotates to cause thephase flexible printed circuit board 107-3 to output a different signal(phase signal). Therefore, by comparing phase signals from the phaseflexible printed circuit board 107-3, it is possible to determinewhether or not the photographic lens unit A16 was mounted/removed.

Next, an example of operation of the digital single-lens reflex cameraaccording to the first embodiment will be described with reference toFIGS. 2 and 13. In FIG. 13, a power-on state means a state where when aphotographer operates any of the operation members A02, the cameraperforms an operation corresponding to the operated operation memberA02. A power-off state means a state where even if the photographeroperates any other operation member A02 than the power switch member102, the camera never performs an operation corresponding to theoperated operation member A02. When the power switch member 102 isoperated, the power-off state is switched to a state where the camera isallowed to perform an operation corresponding to an operation by thephotographer. The power-off state may include a sleep state as apower-saving state where the operation of the camera is temporarilystopped. In this case, when the photographer executes an operation forshooting e.g. by operating the release button 104, the sleep state isswitched to the state where the camera is allowed to perform anoperation corresponding to an operation by the photographer, butotherwise, the camera is not allowed to perform an operationcorresponding to an operation by the photographer. The operation formounting/removing the photographic lens unit A16 is not a directoperation for shooting, and therefore the sleep state is maintained. Itshould be noted that the power-on state shifts to the sleep state whennone of the operation members A02 has been operated over a predeterminedtime period.

First, when a power-off operation is carried out using the power switchmember 102 in a step S100, the process proceeds to a step S101. In thestep S101, the phase flexible printed circuit board 107-3 as a positiondetecting unit A09 detects position information indicative of a positionof the contact brush 107-4 immediately after execution of the power-offoperation.

Then, in a step S102, the position information detected by the phaseflexible printed circuit board 107-3 is recorded in an internal memory(storage unit) A10. Although in the present embodiment, the positioninformation on the contact brush 107-4 is detected and recordedimmediately after execution of the power-off operation, this is notlimitative, but position information on the contact brush 107-4 may beperiodically detected to record an item of position information detectedimmediately before power-off.

After the position information on the contact brush 107-4 is recorded inthe internal memory A10 in the step S102, the process proceeds to a stepS103, wherein the camera enters the power-off state.

When the power is turned off by the operation of the power switch member102, the system stops, and never performs an operation corresponding toa photographer's operation on an operation member A02 until a power-onoperation is carried out using the power switch member 102, even if anyother operation member A02 is operated (step S104). Insofar as theoperation of the release button 104 for returning the camera from thesleep state to the ON state is concerned, it may be checked by interrupthandling in the step S104 whether or not the release button 104 has beenoperated.

If it is determined in the step S104 that power-on operation has beencarried out, the power is turned on to activate the system, followed bythe process proceeding to a step S105.

In the step S105, position information on the contact brush 107-4immediately after execution of the power-on operation is detected by thephase flexible printed circuit board 107-3 as the position detectingunit A09, and in a step S106, the position information detected by thephase flexible printed circuit board 107-3 is recorded in the internalmemory (storage unit) A10.

After the position information on the contact brush 107-4 detectedimmediately after execution of the power-on operation is recorded in theinternal memory A10, the process proceeds to a step S107, wherein adetermination unit A11 performs a comparison between the positioninformation detected immediately after execution of the power-offoperation and the position information detected immediately afterexecution of the power-on operation, both of which have been recorded inthe internal memory A10. If the two items of position information areidentical, it is judged that a photographic lens mounting/removingoperation was not performed, and the process proceeds to a step S109,wherein the camera enters a shooting standby state. On the other hand,if the two items of position information are not identical, it is judgedthat a photographic lens mounting/removing operation was performed, andthe process proceeds to a step S108, wherein a warning signal is outputto recommend cleaning of the optical member A13, such as a low-passfilter (hereinafter abbreviated as “the LPF”). Then, the processproceeds to the step S109, wherein the camera enters the shootingstandby state.

It is desired that cleaning of the optical member A13 is recommendede.g. by causing the camera microcomputer (processing unit) A01 todisplay a message, such as “An image of dust can be picked up” or“Cleaning of the low-pass filter is recommended”, on a display unit A12(e.g. a liquid crystal display for monitoring picked-up images).Alternatively, an alarm advising cleaning of the optical member A13 maybe given by sound.

As described above, according to the present embodiment, when theposition information on the contact brush 107-4 that moves in a mannerinterlocked with the operation of the unlock button 107 differsimmediately after execution of the power-on operation from that obtainedimmediately after execution of the power-off operation, it is judgedthat a photographic lens mounting/removing operation was carried outduring the power-off state, and warning is executed to advise cleaningof the optical member A13.

As a consequence, even if a photographic lens mounting/removingoperation is carried out in the power-off state or with the batteryremoved from the camera, resulting in attachment of dust to the opticalmember A13, since the above-mentioned warning is given, the dust can becleaned off the optical member A13 before shooting is performed. Thus,it is possible to avoid picking up the image of the dust to therebyprevent degradation of image quality. It should be noted that even inthe power-on state, whether or not a photographic lens mounting/removingoperation was carried out may be determined by comparing items ofposition information on the contact brush 107-4 that moves in a mannerinterlocked with the operation of the unlock button 107.

Next, a digital single-lens reflex camera according to a secondembodiment of the present invention will be described with reference toFIGS. 14 to 23. FIG. 14 is a perspective view of a lens mount and itssurrounding of the digital single-lens reflex camera according to thesecond embodiment, as viewed from the object side, in a state where thephotographic lens unit is removed. Component parts and elementsidentical to those of the first embodiment are designated by identicalreference numerals, and description thereof is omitted.

As shown in FIG. 14, the lens mount 105 is formed with three camerabody-side bayonet lugs (engaging part) 105-a for bayonet engagement ofthe photographic lens unit A16 with the camera body 100. The bayonetlugs are each arranged at every 120° position in a manner eachcircumferentially extending over a range of approximately 60°. A linkagepin (rectilinear slide member) 200 is disposed between twocircumferentially adjacent bayonet lugs 105-a (i.e. in an area where abayonet lug 250-a (see FIG. 18) of the photographic lens unit A16 passeswhen the photographic lens unit A16 is mounted/removed to/from thecamera body 100).

The linkage pin 200 is mounted to a mirror box 201 containing the quickreturn mirror 115, in a state movable along the lens optical axis andrestrained from rotation. Although in the present embodiment, thelinkage pin 200 is disposed in the vicinity of the unlock button 204,this is not limitative, but the linkage pin 200 may be mounted to themirror box 201 at any location including other than the vicinity of theunlock button 204, insofar as interference with the bayonet lugs 105-acan be avoided.

FIG. 15 is a perspective view of the mirror box 201, as viewed from thephotographer side. A mechanism operated in a manner interlocked with anoperation for mounting/removing the photographic lens unit A16 to/fromthe camera body-side bayonet lugs 105-a is fixed to the mirror box 201by securing a cam base plate 203 to the mirror box 201 with screws, notshown.

The lens mount 105 is rigidly secured to the mirror box 201, as shown inFIG. 16, such that the photographic lens unit A16 can be removablymounted to the lens mount 105. The mirror box 201 has a through hole201-b formed therethrough, and a fitting shaft 200-b of the linkage pin200 is fitted through the through hole 201-b in a state restrained fromrotation.

Further, the linkage pin 200 is integrally formed with a linkage cam200-a having the same shape as the button cam 107-2-a in the firstembodiment. A compression spring 202 for urging the linkage pin 200toward the object side is disposed on an inner diameter side of thelinkage cam 200-a. The photographer-side inner wall of the mirror box201 is formed with a mirror box cam 201-a having the same shape as thecover cam 112-2-a in the first embodiment.

As a member for cam engagement with the linkage cam 200-a and the mirrorbox cam 201-a, there is provided the rotary cam member (rotary member)107-5 as in the first embodiment. The rotary cam member 107-5 has thecontact brush (movable unit) 107-4 and the compression spring 107-6attached thereto. Further, the mirror box cam 201-a is surrounded by thephase flexible printed circuit board (position detecting unit) 107-3having conductive traces for detecting the position of the contact brush107-4.

The operation for detecting the position of the contact brush 107-4 bythe phase flexible printed circuit board 107-3 as the rotary cam member107-5 rotates is the same as that in the first embodiment, and thereforedescription thereof is omitted.

Next, a description will be given of the mechanism operated in a mannerinterlocked with the operation for mounting/removing the photographiclens unit A16 to/from the camera body-side bayonet lugs 105-a.

As shown in FIG. 17, bayonet holding springs 204 are arranged on thephotographer side of the lens mount 105. When the photographic lens unitA16 is mounted, each of the bayonet holding springs 204 gives anassociated bayonet lug 105-a an urging force acting along the lensoptical axis.

FIG. 18 shows a photographic lens mount 250 of the photographic lensunit A16 in a state fitted in the lens mount 105. In FIG. 18,representation of the other parts of the photographic lens unit A16 thanthe photographic lens mount 250 is omitted. The photographic lens mount250 has three lens-side bayonet lugs 250-a arranged at every 120°position.

When the photographic lens mount 250 is fitted in the lens mount 105,the lens-side bayonet lugs 250-a are mounted at a predetermined phasewhere interference with the camera body-side bayonet lugs 105-a isavoided. At this time, the linkage pin 200 is pushed by thephotographer-side end face of one of the lens-side bayonet lugs 250-aand is moved toward the photographer side to be inserted into the mirrorbox 201. This operation corresponds to the depression of the unlockbutton 107 in the first embodiment.

FIG. 19 shows a state of the lens mount 105 in which the photographiclens unit A16 has been rotated through 60° to a predetermined phaseafter fitting the photographic lens mount 250 of the photographic lensunit A16 therein. In this state, the camera body-side bayonet lugs 105-aand the lens-side bayonet lugs 250-a are held in a state urged againsteach other by the respective bayonet holding springs 204. The rotationof the photographic lens unit A16 brings the area where the linkage pin200 is provided to an area outside the lens-side bayonet lugs 250-a.Therefore, the linkage pin 200 is shifted to the object-side position bythe urging force of the compression spring 202 and is held in a stateprojected from the end face of the mirror box 201.

Next, the above-mentioned operation will be described in detail withreference to FIGS. 20 to 23.

FIG. 20 shows a state of a portion of the lens mount 105 in which thephotographic lens unit A16 is being mounted therein. At this time, thelinkage pin 200 is in a state projected from the end face of the mirrorbox 201.

FIG. 21 shows a state of a portion of the lens mount 105 in which thephotographic lens unit A16 has been pushed therein at the predeterminedphase when mounting the photographic lens unit A16 thereto. At thistime, the linkage pin 200 has been shifted to the photographer-sideposition by being pushed by the end face of the associated lens-sidebayonet lug 250-a.

FIG. 22 shows a state of a portion of the lens mount in which thephotographic lens unit A16 is being rotated to the predetermined phase,and in the illustrated state, the photographic lens unit A16 has beenrotated through approximately 30°. In FIG. 22, the lens-side bayonet lug250-a is moved downward, as viewed in FIG. 22, but in actuality, it isrotated about the lens optical axis. Further, the lens-side bayonet lug250-a has started to disengage from a tapered part 200-c formed on thelinkage pin 200, i.e. the linkage pin 200 has started to be moved towardthe object side by the urging force of the compression spring 202 andthe tapered part 200-c.

FIG. 23 shows a state of a portion of the lens mount 105 in which thephotographic lens unit A16 has been fully rotated to the predeterminedphase and is completely mounted to the camera body 100. In this state,the linkage pin 200 has been shifted to its initial position and heldthere. It should be noted that an operation for removing thephotographic lens unit A16 is just the reverse of the operation formounting the same, and hence description thereof is omitted.

The above-described sequential operation corresponds to the operation ofdepressing and releasing the unlock button 107 in the first embodiment.In the operation, the mirror box cam 201-a, the linkage cam 107-5-a, andthe rotary cam 107-5-a are brought into contact with each other tothereby rotate the rotary cam member 107-5 and the contact brush 107-4.

Then, the rotation of the contact brush 107-4 changes one phase signaldetected by the phase flexible printed circuit board 107-3 to another,as in the above-described first embodiment, which makes it possible todetermine whether or not the photographic lens unit A16 wasmounted/removed. Although in the present embodiment, the operation formounting the photographic lens unit is described, the present embodimentcan be applied to an operation for mounting a lens mount cap to bemounted on the lens mount 105 when the camera is not used.

As described above, according to the present embodiment, when theposition information on the contact brush 107-4 operated in a mannerinterlocked with the operation for mounting/removing the photographiclens unit A16 to/from the bayonet lugs 105-a differs immediately afterexecution of a power-on operation from that obtained immediately afterexecution of a power-off operation, it is judged that photographic lensmounting/removing operation was carried out during the power-off state,and warning is executed to advise cleaning of the optical member A13.

As a consequence, even if a photographic lens mounting/removingoperation is carried out in the power-off state or with the batteryremoved from the camera, resulting in attachment of dust to the opticalmember A13, since the above-mentioned warning is given, the dust can becleaned off the optical member A13 before shooting is performed. Thus,it is possible to avoid picking up the image of the dust to therebyprevent degradation of image quality. It should be noted that even inthe power-on state, whether or not a photographic lens mounting/removingoperation was carried out may be determined by comparing the items ofposition information on the contact brush 107-4 operated in a mannerinterlocked with the operation for mounting/removing the photographiclens unit A16 to/from the bayonet lugs 105-a.

Next, a digital single-lens reflex camera according to a thirdembodiment of the present invention will be described with reference toFIGS. 24 to 30. FIG. 24 is a perspective view of an unlock button andits surrounding of the digital single-lens reflex camera according tothe third embodiment. In FIG. 24, a front cover is omitted fromillustration. Component parts and elements identical to those of thefirst embodiment are designated by identical reference numerals, anddescription thereof is omitted.

As shown in FIG. 24, the unlock button (unlocking member) 307 is held ina state urged toward the object side, by a fall-off prevention mechanismusing a front cover (not shown) and an E ring 306 and the urging forceof a compression spring 308.

FIG. 25 is an exploded perspective view of a mechanism operated in amanner interlocked with an operation of the unlock button 307. Disposedon the photographer side of the unlock button 307 is a linkage lever 300that can move along the lens optical axis in accordance with movement ofthe unlock button 307 along the lens optical axis. The linkage lever 300has portions, referred to hereinafter, thereof fitted in fitting holes301-a and 301-b formed in a lever base plate 301 whereby it is held in astate movable along the lens optical axis and restrained from rotation.

The linkage lever 300 is formed with a detected arm (movable unit) 300-athat moves in and out of a detector part of a photointerrupter 302(hereinafter referred to as “the PI 302”) attached to the lever baseplate 301. Further, the linkage lever 300 is formed with a lever dowel300-b for fixing one end of a toggle spring 303 for urging the linkagelever 300 toward the object side or the photographer side.

The lever base plate 301 is formed with a base plate dowel 301-d forfixing the other end of the toggle spring 303, an PI mounting part 301-cfor mounting the PI 302, and a slot 301-b for preventing rotation of thelinkage lever 300. The lever dowel 300-b is fitted through the slot(fitting hole) 301-b. The lever base plate 301 is rigidly secured to amirror box 309 with screws, not shown, in a state holding the mechanismoperated in a manner interlocked with the operation of the unlock button307.

Further, a motor (drive unit) 305 is mounted to the lever base plate 301such that its rotating shaft 305-a extends through a through hole 301-eformed in the lever base plate 301 and projects toward the linkage lever300. The linkage lever 300 is driven by the motor 305 to move along thelens optical axis. A drive arm 304 attached to the rotating shaft 305-aof the motor 305 by having the rotating shaft 305-a fixedly fittedthrough a mounting hole 304-b thereof is formed with a slot 304-a forfitting on the lever dowel 300-b protruding from the linkage lever 300.This slot 304-a allows the linkage lever 300 to move along the lensoptical axis. Although in the present embodiment, the linkage lever isdriven by the rotary motor to move along the lens optical axis, adifferent type of drive unit, such as a solenoid, may be used to movethe linkage lever.

FIG. 26 is a see-through view (in which the front cover is not shown)showing the internal construction of the mechanism operated in a mannerinterlocked with the operation of the unlock button 307.

As shown in FIG. 26, the unlock button 307 is urged toward the objectside by the compression spring 308 and is held in a predeterminedposition. The toggle spring 303 generates an urging force acting in adirection for moving the lever dowel 300-b away from the base platedowel 301-d, to thereby urge the linkage lever 300 toward the objectside. The linkage lever 300 is held in contact with thephotographer-side end of the unlock button 307 by the urging force ofthe toggle spring 303. At this time, the detected arm 300-a is in aposition where it has moved out from the detector part of the PI 302.The motor 305 is in a deenergized state.

FIG. 27 shows the unlock button 307 in a depressed state. In FIG. 27,the lever base plate 301 and the compression spring 308 are omitted fromillustration.

As shown in FIG. 27, when the unlock button 307 is depressed toward thephotographer side, the end of the unlock button 307 pushes the linkagelever 300 toward the photographer side, and therefore the linkage lever300 is also moved toward the photographer side. The lever dowel 300-band the base plate dowel 301-d are positioned such that the turningpoint of the toggle spring 303 corresponds to approximately half theamount of depression of the unlock button 307. With this arrangement,when depression of the unlock button 307 is completed, the direction inwhich the toggle spring 303 urges the linkage lever 300 is reversed,whereby the linkage lever 300 can be changed into a state urged towardthe photographer side.

In the state where the linkage lever 300 is urged toward thephotographer side, the detected arm 300-a is in a position inserted inthe detector part of the PI 302. Although in the present embodiment, thePI is employed as a position detecting unit, this is not limitative, butit is possible to employ any suitable detector element having a movablepart that operates in a manner interlocked with the detected arm.

FIG. 28 shows a state where the unlock button 307 has been releasedafter depression. In this state, the unlock button 307 is urged andmoved toward the object side by the compression spring 308 and is heldin a predetermined position by abutment of the E ring 306 with the frontcover.

On the other hand, the linkage lever 300 is held in a state shifted tothe photographer-side position by the urging force of the toggle spring303 acting in the direction toward the photographer side. Morespecifically, once the unlock button 307 is operated so as to remove thephotographic lens unit, the linkage lever 300 is held in the stateshifted to the photographer-side position. In the state where thelinkage lever 300 is urged toward the photographer side, the detectedarm 300-a is in a position inserted in the detector part of the PI 302.

Therefore, based on whether or not the detected arm 300-a is detected bythe PI 302, it is possible to determine whether or not the unlock button307 was operated, i.e. whether or not an operation for mounting/removingthe photographic lens unit C16 (see FIG. 29) was carried out.

FIG. 29 is a control block diagram of the digital single-lens reflexcamera according to the third embodiment. FIG. 30 is a flowchart usefulin explaining an example of operation of the digital single-lens reflexcamera according to the third embodiment.

The process shown FIG. 30 will be described while referring to FIG. 29.When a power-off operation is carried out in a step S300 in FIG. 30, theprocess proceeds to a step S301.

In the step S301, a camera microcomputer C01 drives the PI 302 as aposition detecting unit C09 to detect whether or not the detected arm300-a of the linkage lever 300 is engaged in the PI 302, and obtainsposition information on the linkage lever 300 as a result of thedetection, i.e. obtains position information on the linkage lever 300concerning whether it is held on the object side or on the photographerside. Although in the present embodiment, it is detected after executionof the power-off operation whether or not the detected arm 300-a isinserted in the PI 302, this is not limitative, but whether or not thedetected arm 300-a is inserted in the PI 302 may be periodicallydetected and use the position information on the detected arm 300-aobtained immediately before turn-off of the power.

In a step S302, it is determined, based on the position informationobtained in the step S301, whether or not the linkage lever 300 is heldon the object side. If it is determined that the linkage lever 300 isheld on the object side, the process proceeds to a step S303, whereinthe camera enters the power-off state. On the other hand, if it isdetermined that the linkage lever 300 is held on the photographer side,the process proceeds to a step S304.

In the step S304, the camera microcomputer C01 drives the motor 305 as adrive unit C14 to shift the linkage lever 300 to the object-sideposition. When the linkage lever 300 is shifted to the object-sideposition, the detected arm 300-a is moved out of the PI 302. In responsethereto, the camera microcomputer C01 stops driving the motor 305, basedon a change in a signal from the PI 302, and the process proceeds to thestep S303, wherein the camera enters the power-off state. In short,after execution of the power-off operation, the linkage lever 300 iscaused to be always in a state shifted to the object-side position. Evenin the power-off state, the linkage lever 300 is constantly held on theobject side by the urging force of the toggle spring 303.

When the power is turned off by the operation of the power switch member102, the system stops and never performs an operation until an power-onoperation is carried out using the power switch member 102, even if anyother operation member A02 is operated (step S305). Insofar as theoperation of the release button 104 for returning the camera from thesleep state to the ON state is concerned, it may be checked by interrupthandling in the step S305 whether or not the release button 104 wasoperated.

If it is determined in the step S305 that power-on operation has beencarried out, the power is turned on to activate the system, and theprocess proceeds to a step S306.

In the step S306, immediately after execution of the power-on operation,the camera microcomputer C01 drives the PI 302 as the position detectingunit C09 to detect whether or not the detected arm 300-a of the linkagelever 300 is in the position inserted in the PI 302, and obtainsposition information on the linkage lever 300 as a result of thedetection, i.e. obtains position information on the linkage lever 300concerning whether it is held on the object side or on the photographerside.

Then, in a step S307, it is determined, based on the positioninformation obtained in the step S306, whether or not the linkage lever300 is held on the object side. If it is determined that the linkagelever 300 is held on the object side, a determination unit C11 judgesthat a photographic lens mounting/removing operation was not carriedout, and the process proceeds to a step S309, wherein the camera entersthe shooting standby state. On the other hand, if it is determined inthe step S307 that the linkage lever 300 is held on the photographerside, the determination unit C11 judges that a photographic lensmounting/removing operation was carried out, and the process proceeds toa step S308.

In the step S308, a warning signal advising cleaning of an opticalmember C13, such as an LPF, is output, and then the process proceeds tothe step S309, wherein the camera enters the shooting standby state.

It is desired that cleaning of the optical member C13 is advised e.g. bycausing the camera microcomputer (processing unit) C01 to display amessage, such as “An image of dust can be picked up” or “Cleaning of thelow-pass filter is recommended”, on a display unit C12 (e.g. a liquidcrystal display for monitoring picked-up images). Alternatively, analarm advising cleaning of the optical member C13 may be given usingsound.

As described above, according to the present embodiment, when theposition information on the linkage lever 300, i.e. the detected arm300-a that moves in a manner interlocked with the operation of theunlock button 307 differs immediately after execution of a power-onoperation from that obtained immediately after execution of a power-offoperation, it is judged that a photographic lens mounting/removingoperation was carried out during the power-off state, and warning isexecuted to advise cleaning of the optical member C13.

As a consequence, even if a photographic lens mounting/removingoperation is carried out in the power-off state or with the batteryremoved from the camera, resulting in attachment of dust to the opticalmember C13, since the above-mentioned warning is given, the dust can becleaned off the optical member C13 before shooting is performed. Thismakes it possible to avoid picking up the image of the dust to therebyprevent degradation of image quality. It should be noted that even inthe power-on state, whether or not photographic lens mounting/removingoperation was carried out may be determined by comparing the items ofposition information on the detected arm 300-a that moves in a mannerinterlocked with the operation of the unlock button 307.

Next, a digital single-lens reflex camera according to a fourthembodiment of the present invention will be described with reference toFIGS. 31 to 33. FIG. 31 is a perspective view of an unlock button andits surrounding of the digital single-lens reflex camera according tothe fourth embodiment. FIG. 32 is an exploded perspective view of amechanism operated in a manner interlocked with a bayonet engagementoperation (photographic lens unit mounting/removing operation).

The present embodiment is distinguished from the above-described thirdembodiment in which determination as to a photographic lensmounting/removing operation is performed by comparing items of positioninformation on the detected arm 300-a that moves in a manner interlockedwith the operation of the unlock button 307, only in that thedetermination is performed by comparing items of position information ofa detected arm 400-a that moves in a manner interlocked with a bayonetengagement operation (see the second embodiment). The mechanism operatedin a manner interlocked with bayonet engagement operation issubstantially the same as the mechanism operated in a manner interlockedwith the operation of the unlock button 307. Therefore, component partsand elements identical to those of the third embodiment are designatedby identical reference numerals, and description thereof is omitted.

As shown in FIGS. 31 and 32, in the digital single-lens reflex cameraaccording to the fourth embodiment, a linkage lever 400 is disposed in amanner protruding from an end face of a mirror box 401, and has an endthereof formed as a tapered part 400-c. A motor base plate 402(corresponding to the lever base plate 301 in the third embodiment) onwhich is mounted the motor 305 is rigidly secured to the mirror box 401with screws, not shown.

The tapered part 400-c of the linkage lever 400 is identical in shape tothe tapered part 200-c of the linkage lever 200. Further, a mechanismfor moving the linkage lever 400 along the lens optical axis in a mannerinterlocked with a photographic lens mounting/removing operation is thesame as the mechanism, described in the second embodiment, for movingthe linkage pin 200 along the lens optical axis in a manner interlockedwith the photographic lens mounting/removing operation.

The linkage lever 400 is formed with a detected arm (movable unit) 400-afor being inserted in the detector part of the PI 302, and a lever dowel400-b for fixing one end of the toggle spring 303. The detected arm400-a and the lever dowel 400-b are identical in shape to the detectedarm 300-a and the lever dowel 300-b formed in the linkage lever 300described in the third embodiment.

A motor base plate 402 is formed with a base plate dowel 402-d forfixing the other end of the toggle spring 303, a PI mounting part 402-cfor mounting the PI 302 for detecting the position of the linkage lever400, and a slot 402-b for preventing rotation of the linkage lever 400.The base plate dowel 402-d, the PI mounting part 402-c, and the slot402-b are identical in shape to the base plate dowel 301-b, the PImounting part 301-c, and the slot 301-b for preventing rotation, in thethird embodiment.

FIG. 33 is a cross-sectional view of the mirror box 401 with the lensmount 105 rigidly secured thereto. The linkage lever 400 is held in themirror box 401 in a manner movable along the lens optical axis andrestrained from rotation. The linkage lever 400 is held in a stateshifted to the object side or the photographer side by the urging forceof the toggle spring 303.

An operation of pushing the linkage lever 400 toward the photographerside by the lens-side bayonet lugs is identical to the operation ofpushing in the linkage pin 200 toward the photographer side by thelens-side bayonet lugs in the second embodiment, and hence descriptionthereof is omitted. Further, a mechanism using the toggle spring 303 tohold the state where the linkage lever 400 is pushed toward thephotographer side is identical to the mechanism in the third embodiment,which uses the toggle spring 303 to hold the state where the linkagelever 300 is pushed toward the photographer side, and hence descriptionthereof is also omitted.

The basic operation of the present embodiment is the same as that of thethird embodiment described with reference to FIG. 30, and therefore onlythe outline thereof will be described here. Control is performed suchthat the linkage lever 400 is always held in a state shifted to theobject side immediately after execution of the power-off operation.

Then, if the linkage lever 400 is held on the object side immediatelyafter execution of the power-on operation, it is determined that aphotographic lens mounting/removing operation was not carried out. Onthe other hand, if the linkage lever 400 is held on the photographerside, it is determined that the photographic lens mounting/removingoperation was carried out, and a warning is displayed on the displayunit (e.g. a liquid crystal display for monitoring picked-up images) toadvise cleaning of the optical member, such as an LPF.

As described above, according to the present embodiment, when theposition information on the detected arm 400-a that moves in a mannerinterlocked with the photographic lens mounting/removing operationdiffers immediately after execution of a power-on operation from thatobtained immediately after execution of a power-off operation, it isjudged that the photographic lens mounting/removing operation wascarried out during the power-off state, and warning is executed toadvise cleaning of the optical member, such as an LPF.

As a consequence, even if the photographic lens mounting/removingoperation is carried out in the power-off state or with the batteryremoved from the camera, resulting in attachment of dust to the opticalmember, such as an LPF, since the above-mentioned warning is given, thedust can be cleaned off the optical member before shooting is performed.This makes it possible to avoid picking up the image of the dust tothereby prevent degradation of image quality. It should be noted thateven in the power-on state, whether or not a photographic lensmounting/removing operation was carried out may be determined bycomparing items of position information on the detected arm 400-a thatmoves in a manner interlocked with the photographic lensmounting/removing operation.

Next, a digital single-lens reflex camera according to a fifthembodiment of the present invention will be described with reference toFIGS. 34 to 36. FIG. 34 is a cross-sectional view of essential parts ofthe digital single-lens reflex camera according to the fifth embodiment.The present embodiment is distinguished from the first embodiment onlyin that there is additionally provided a dust-removing unit for removingdust from an optical member, such as an LFP. Therefore, descriptionoverlapping that of the first embodiment is omitted.

As shown in FIG. 34, a mirror box 500 contains a quick return mirror501. An LPF 503 (E13) as an optical member is disposed on the objectside of an electronic image pickup element 502, and a piezoelectricelement (vibrator unit) 504 for providing vibration to the LPF 503 isdisposed between the LPF 503 and a finder optical system 505.

Control is performed such that the piezoelectric element 504 disposed inthe vicinity of the LPF 503 is driven for vibration to cause resonancevibration in the LPF 503, whereby dust attached to the surface of theLFP 503 can be removed. As shown in FIG. 35, a shutter mechanism E05 isdisposed between the LPF 503 and the quick return mirror 501. Althoughin the present embodiment, dust attached to the LFP 503 is removed bycausing the piezoelectric element to provide vibration to the LFP 503,this is not limitative, but other methods (e.g. a wiping method) may beemployed to remove dust.

Next, an example of operation of the digital single-lens reflex cameraaccording to the fifth embodiment will be described with reference toFIGS. 35 and 36. FIG. 35 is a control block diagram of the digitalsingle-lens reflex camera according to the fifth embodiment, and FIG. 36is a flowchart useful in explaining the process of the digitalsingle-lens reflex camera according to the fifth embodiment. Componentparts and elements identical to those of the first embodiment aredesignated by identical reference numerals.

First, when a power-off operation is carried out in a step S500 in FIG.36, the process proceeds to a step S501. In the step S501, positioninformation on the contact brush 107-4 is obtained as a result ofdetection of a position of the contact brush 107-4 immediately afterexecution of the power-off operation, by the phase flexible printedcircuit board 107-3 as a position detecting unit E09.

Then, in a step S502, the position information detected by the phaseflexible printed circuit board 107-3 immediately after execution of thepower-off operation is recorded in an internal memory (storage unit)E10. Although in the present embodiment, the position information on thecontact brush 107-4 is detected and recorded immediately after executionof the power-off operation, this is not limitative, but the positioninformation on the contact brush 107-4 may be periodically detected tostore an item of position information obtained immediately beforepower-off.

After the position information on the contact brush 107-4 is recorded inthe internal memory E10 in the step S502, the process proceeds to a stepS503, wherein the camera enters the power-off state.

When the power is turned off by operation of the power switch member102, the system stops and never performs an operation until a power-onoperation is carried out by the power switch member 102, even if anyother operation member A02 is operated (step S504). Insofar as theoperation of the release button 104 for returning the camera from thesleep state to the ON state is concerned, it may be checked by interrupthandling in the step S504 whether or not the release button 104 wasoperated.

If it is determined in the step S504 that the power-on operation hasbeen carried out, the power is turned on to activate the system, and theprocess proceeds to a step S505.

In the step S505, position information on the contact brush 107-4immediately after execution of the power-on operation is detected by thephase flexible printed circuit board 107-3 as the position detectingunit E09, and in a step S506, the position information detected by thephase flexible printed circuit board 107-3 is recorded in the internalmemory (storage unit) E10.

After the position information on the contact brush 107-4 detectedimmediately after execution of the power-on operation is recorded in theinternal memory E10, the process proceeds to a step S507, wherein adetermination unit E11 performs a comparison between the item ofposition information detected immediately after execution of thepower-off operation and the item of position information detectedimmediately after execution of the power-on operation, both of whichhave been stored in the internal memory E10. If the two items ofposition information are identical, it is judged that a photographiclens mounting/removing operation was not performed, and the processproceeds to a step S508. On the other hand, if the two items of positioninformation are not identical, it is judged that a photographic lensmounting/removing operation was performed, and the process proceeds to astep S509.

In the step S508, a camera microcomputer (processing unit) E01 performsa first control to cause the piezoelectric element 504 as a vibratorunit E14 not to be driven, and then the process proceeds to a step S510,wherein the camera enters the shooting standby state.

On the other hand, in the step S509, the camera microcomputer(processing unit) E01 performs a second control to cause thepiezoelectric element 504 as the vibrator unit E14 to be driven toprovide vibration to the LPF 503 as the optical member E13, and then theprocess proceeds to the step S510, wherein the camera enters theshooting standby state.

As described above, in the present embodiment, the first control causesthe piezoelectric element 504 not to be driven, whereas the secondcontrol causes the piezoelectric element 504 to be driven for apredetermined time period. However, this is not limitative.

For example, the first control may be configured such that thepiezoelectric element 504 is driven over a predetermined time period. Inthis case, the second control causes the piezoelectric element 504 to bedriven for a longer time period than by the first control. No matter howthe first and second control processes may be varied, when it isdetermined that a photographic lens mounting/removing operation wasperformed, the dust-removing unit is driven by a control which canprovide a higher dust removing effect than when the photographic lensmounting/removing operation was not performed.

As described above, according to the present embodiment, when theposition information on the contact brush 107-4 operated in a mannerinterlocked with the operation of the unlock button 107 differsimmediately after execution of a power-on operation from that obtainedimmediately after execution of a power-off operation, it is judged thata photographic lens mounting/removing operation was performed during thepower-off state, and processing for providing vibration to the opticalmember E13 is executed.

As a consequence, even if the photographic lens mounting/removingoperation is performed in the power-off state or with the batteryremoved from the camera, resulting in attachment of dust to the opticalmember E13, the dust can be cleaned off the optical member E13 byvibrating the optical member E13, before shooting is performed. Thismakes it possible to avoid picking up the image of the dust to therebyprevent degradation of image quality.

It should be noted that even in the power-on state, whether or not aphotographic lens mounting/removing operation was carried out may bedetermined by comparing the items of position information on the contactbrush 107-4 operated in a manner interlocked with the operation of theunlock button 107. Further, although in the present embodiment, thedust-removing unit for removing dust from the optical member, such as anLPF, is added to the first embodiment, the dust-removing unit may beadded to the second embodiment.

Next, a digital single-lens reflex camera according to a sixthembodiment of the present invention will be described with reference toFIGS. 37 and 38. FIG. 37 is a flowchart useful in explaining an exampleof operation of the digital single-lens reflex camera according to thesixth embodiment, and FIG. 38 is a control block diagram of the digitalsingle-lens reflex camera. The present embodiment is distinguished fromthe third embodiment only in that as in the fifth embodiment, there isadditionally provided a dust-removing unit for removing dust from anoptical member, such as an LFP. Therefore, description overlapping thatof the third embodiment is omitted.

In the following, the example of the process of the digital single-lensreflex camera according to the sixth embodiment will be described withreference to FIGS. 37 and 38. Component parts and elements identical tothose of the third and fifth embodiments are designated by identicalreference numerals.

First, when a power-off operation is carried out in a step S600 in FIG.37, the process proceeds to a step S601.

In the step S601, a camera microcomputer F01 drives the PI 302 as aposition detecting unit F09 to detect whether or not the detected arm300-a of the linkage lever 300 is in a position inserted in the PI 302,and obtains position information on the detected arm 300-a of thelinkage lever 300 as a result of the detection, i.e. positioninformation on the linkage lever 300 concerning whether the linkagelever 300 is held on the object side or on the photographer side.Although in the present embodiment, it is detected after execution ofthe power-off operation whether or not the detected arm 300-a isinserted in the PI 302, this is not limitative, but whether or not thedetected arm 300-a is inserted in the PI 302 may be periodicallydetected to thereby employ a position information item of the detectedarm 300-a obtained immediately before the power is turned off.

In a step S602, it is determined, based on the position informationdetected in the step S601, whether or not the linkage lever 300 is heldon the object side. If it is determined that the linkage lever 300 isheld on the object side, the process proceeds to a step S603, wherein ifit is determined in the step S602 that the linkage lever 300 is held onthe photographer side, the process proceeds to a step S604.

In the step S604, the camera microcomputer F01 drives the motor 305 as adrive unit F14 to shift the linkage lever 300 to the object side. Whenthe linkage lever 300 is shifted to the object side, the detected arm300-a is moved out of the PI 302. Therefore, the camera microcomputerF01 stops driving the motor 305, based on a change in a signal from thePI 302, and the process proceeds to the step S603, wherein the cameraenters the power-off state. In short, after execution of the power-offoperation, the linkage lever 300 is caused to be always in a stateshifted to the object side. Even in the power-off state, the linkagelever 300 is constantly held on the object side by the urging force ofthe toggle spring 303.

When the power is turned off by the operation of the power switch member102, the system stops and never performs an operation until a power-onoperation is carried out by the power switch member 102, even if anyother operation member A02 is operated (step S605). Insofar as theoperation of the release button 104 for returning the camera from thesleep state to the ON state is concerned, it may be checked by interrupthandling in the step S605 whether or not the release button 104 wasoperated.

If it is determined in the step S605 that power-on operation has beencarried out, the power is turned on to activate the system, and theprocess proceeds to a step S606.

In the step S606, immediately after execution of the power-on operation,the camera microcomputer F01 drives the PI 302 as the position detectingunit F09 to detects whether or not the detected arm 300-a of the linkagelever 300 is in the position inserted in the PI 302, i.e. obtainsposition information on the linkage lever 300 as a result of thedetection, i.e. obtains position information on the linkage lever 300concerning whether it is held on the object side or on the photographerside.

Then, in a step S607, it is determined, based on the positioninformation detected in the step S606, whether or not the linkage lever300 is held on the object side. If it is determined that the linkagelever 300 is held on the object side, a determination unit F11 judgesthat the photographic lens mounting/removing operation was not carriedout, and the process proceeds to a step S608. On the other hand, if itis determined in the step S607 that the linkage lever 300 is held on thephotographer side, the determination unit F11 judges that thephotographic lens mounting/removing operation was carried out, and theprocess proceeds to a step S609.

In the step S608, the camera microcomputer (processing unit) F01performs a first control to cause the piezoelectric element 504 as avibrator unit F15 to be driven, and then the process proceeds to a stepS610, wherein the camera enters the shooting standby state.

On the other hand, in the step S609, the camera microcomputer(processing unit) F01 performs a second control to cause thepiezoelectric element 504 as the vibrator unit F15 to be driven toprovide vibration to the LPF 503 as the optical member F13, and then theprocess proceeds to the step S610, wherein the camera enters theshooting standby state.

As described above, in the present embodiment, the first control causesthe piezoelectric element 504 not to be driven, whereas the secondcontrol causes the piezoelectric element 504 to be driven for apredetermined time period. However, this is not limitative.

For example, the first control may be configured such that thepiezoelectric element 504 is driven for a predetermined time period. Inthis case, the second control causes the piezoelectric element 504 to bedriven for a longer time period than by the first control. No matter howthe first and second control may be varied, when it is determined that aphotographic lens mounting/removing operation was performed, thedust-removing unit is driven by a control which can provide a higherdust removing effect than when the photographic lens mounting/removingoperation was not performed.

As described heretofore, according to the present embodiment, when theposition information on the detected arm 300-a that moves in a mannerinterlocked with the operation of the unlock button 307 differsimmediately after execution of a power-on operation from that obtainedimmediately after execution of a power-off operation, it is judged thata photographic lens mounting/removing operation was carried out duringthe power-off state, and processing for providing vibration to theoptical member F13 is executed.

As a consequence, even if a photographic lens mounting/removingoperation is performed in the power-off state or with a battery removedfrom the camera, resulting in attachment of dust to the optical memberF13, the dust can be cleaned off the optical member F13 by vibrating theoptical member F13, before shooting is performed. Thus, it is possibleto avoid picking up the image of the dust to thereby prevent degradationof image quality.

It should be noted that even in the power-on state, whether or not aphotographic lens mounting/removing operation was carried out may bedetermined by comparing items of position information on the detectedarm 300-a that moves in a manner interlocked with the operation of theunlock button 307. Further, although in the present embodiment, thedust-removing unit for removing dust from the optical member, such as anLPF, is added to the third embodiment, the dust-removing unit may beadded to the fourth embodiment.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed embodiments. The scope of the following claimsis to be accorded the broadest interpretation so as to encompass allsuch modifications and equivalent structures and functions.

This application claims the benefit of Japanese Patent Application No.2006-208652, Jul. 31, 2006 which is hereby incorporated by referenceherein in its entirety.

1. An image pickup apparatus on which a photographic lens is removablyheld, comprising: a movable unit configured to move in a mannerinterlocked with mounting/removing of the photographic lens; a positiondetecting unit configured to detect a position of said movable unit; anda determination unit configured to determine, based on positioninformation on said movable unit detected by said position detectingunit, whether or not the photographic lens was mounted/removed.
 2. Animage pickup apparatus as claimed in claim 1, comprising a processingunit configured to carry out processing for cleaning an optical memberwhen said determination unit determines that the photographic lens wasmounted/removed.
 3. An image pickup apparatus as claimed in claim 2,wherein the optical member is disposed between an image pickup elementfor converting light incident thereon from the photographic lens into anelectric signal, and the photographic lens.
 4. An image pickup apparatusas claimed in claim 1, comprising a storage unit configured to store theposition information on said movable unit detected by said positiondetecting unit, and wherein said determination unit determines, based onthe position information stored in said storage unit, whether or not thephotographic lens was mounted/removed.
 5. An image pickup apparatus asclaimed in claim 1, wherein when the position information on saidmovable unit detected after execution of a power-off operation and theposition information on said movable unit detected after execution of apower-on operation differ from each other, said determination unitdetermines that the photographic lens was mounted/removed.
 6. An imagepickup apparatus as claimed in claim 1, comprising an unlocking memberconfigured to release engagement of the photographic lens, and whereinsaid movable unit moves in a manner interlocked with an operation ofsaid unlocking member.
 7. An image pickup apparatus as claimed in claim6, comprising a movement-converting unit including a rectilinear slidemember configured to be capable of moving along an optical axis of thephotographic lens in a manner interlocked with the operation of saidunlocking member, and a rotary member provided with said movable unitand connected to said rectilinear slide member via a cam engagementpart, said movement-converting unit converting movement of saidrectilinear slide member along the optical axis to rotation of saidrotary member by cam action of the cam engagement part.
 8. An imagepickup apparatus as claimed in claim 1, comprising an engagement unitfor engagement with the photographic lens, and wherein said movable unitmoves in a manner interlocked with an operation for mounting/removingthe photographic lens to/from said engagement unit.
 9. An image pickupapparatus as claimed in claim 8, comprising a movement-converting unitincluding a rectilinear slide member configured to be capable of movingalong an optical axis of the photographic lens in a manner interlockedwith an operation for mounting/removing the photographic lens to/fromsaid engagement unit, and a rotary member provided with said movableunit and connected to said rectilinear slide member via a cam engagementpart, said movement-converting unit converting movement of saidrectilinear slide member along the optical axis to rotation of saidrotary member by cam action of the cam engagement part.
 10. An imagepickup apparatus as claimed in claim 9, wherein said engagement unit hasa plurality of arcuate bayonet lugs circumferentially arranged, and saidrectilinear slide member is disposed between circumferentially adjacentones of said bayonet lugs.
 11. An image pickup apparatus as claimed inclaim 1, wherein said position detecting unit includes a conductivemember provided in said movable unit, and an electric circuit memberhaving a plurality of conductive traces, and said electric circuitmember detects at least two items of position information each accordingto a position of the conductive member.
 12. An image pickup apparatus asclaimed in claim 1, comprising an unlocking member configured to releaseengagement of the photographic lens, and a drive unit configured todrive said movable unit, and wherein said movable unit is configured tobe movable between a first position and a second position, and when apower-off operation is carried out, said movable unit is driven by saiddrive unit to shift to the first position to be held in the firstposition, and when said unlocking member is operated, said movable unitshifts to the second position in a manner interlocked with the operationof said unlocking member, to be held in the second position, and whereinwhen the position information on said movable unit detected afterexecution of the power-off operation and the position information onsaid movable unit detected after execution of the power-on operationdiffer from each other, said determination unit determines that thephotographic lens was mounted/removed.
 13. An image pickup apparatus asclaimed in claim 1, comprising an unlocking member configured to releaseengagement of the photographic lens, and a drive unit configured todrive said movable unit, and wherein said movable unit is configured tobe movable between a first position and a second position, and saidmovable unit is driven by said drive unit to shift to the first positionto be held in the first position, when a power-off operation is carriedout, and shifts to the second position in a manner interlocked with theoperation of said unlocking member, to be held in the second position,and wherein when the position information on said movable unit detectedafter execution of the power-off operation and the position informationon said movable unit detected after execution of a power-on operationdiffer from each other, said determination unit determines that thephotographic lens was mounted/removed.
 14. An image pickup apparatus asclaimed in claim 13, wherein said engagement unit has a plurality ofarcuate bayonet lugs circumferentially arranged, and said movable unitis disposed between circumferentially adjacent ones of said bayonetlugs.
 15. An image pickup apparatus as claimed in claim 12, wherein saidmovable unit is configured to be movable along the optical axis of thephotographic lens, and is provided with a toggle spring for urging saidmovable unit toward one side or an opposite side in a direction alongthe optical axis.
 16. An image pickup apparatus as claimed in claim 13,herein said movable unit is configured to be movable along the opticalaxis of the photographic lens, and is provided with a toggle spring forurging said movable unit toward one side or an opposite side in adirection along the optical axis.
 17. An image pickup apparatus asclaimed in claim 12, wherein said position detecting unit opticallydetects the position of said movable unit.
 18. An image pickup apparatusas claimed in claim 13, wherein said position detecting unit opticallydetects the position of said movable unit.
 19. An image pickup apparatusas claimed in claim 12, wherein said position detecting unitelectrically detects the position of said movable unit.
 20. An imagepickup apparatus as claimed in claim 13, wherein said position detectingunit electrically detects the position of said movable unit.
 21. Animage pickup apparatus as claimed in claim 1, comprising a vibrator unitconfigured to provide vibration to the optical member, and wherein whensaid determination unit determines that the photographic lens was notmounted/removed, said processing unit drives said vibrator unit by afirst control, and when said determination unit determines that thephotographic lens was mounted/removed, said processing unit drives saidvibrator unit by a second control.
 22. An image pickup apparatus asclaimed in claim 21, wherein the first control causes said vibrator unitnot to be driven, and the second control causes said vibrator unit to bedriven for a predetermined time period.
 23. An image pickup apparatus asclaimed in claim 21, wherein the first control causes said vibrator unitto be driven for a predetermined time period, and the second controlcauses said vibrator unit to be driven for a longer time period than thepredetermined time period.
 24. An image pickup apparatus as claimed inclaim 1, wherein when said determination unit determines that thephotographic lens was mounted/removed, said processing unit carries outwarning processing to advise cleaning of the optical member.